1. Field of the Invention
The present invention relates to a paper-sheet storing/feeding machine, a paper-sheet handling machine and a method for storing paper sheets, each adapted for storing and feeding the paper sheets by winding and rewinding a tape.
2. Background Art
As the paper-sheet storing/feeding machine adapted for storing and feeding the paper sheets, such as banknotes or the like, one paper-sheet storing/feeding machine (hereinafter referred to as a “tape-type storing/feeding machine”) including a winding roller designed for winding the paper sheets together with a tape has been known. With the provision of this machine, the paper sheets respectively fed from a transport path can be wound and stored by a winding operation using the winding roller. Further, the paper sheets can be fed out toward the transport path by a rewinding operation using the winding roller. In order to increase the number of the paper sheets stored in this tape-type storing/feeding machine, it is preferred to increase the length of the tape. In addition, the number of the stored paper sheets can be further increased by shortening the length of each part of the tape not used for holding the paper sheets, among the tape wound around the winding roller.
As the method for winding the tape around the winding roller, one approach designed for winding the tape, successively, at a speed controlled to be substantially the same as a transport speed of the paper sheets, has been known. It is true that this approach enables the paper sheets to be stably wound with a relatively simple control operation. However, such an approach is not so advantageous for increasing the number of the stored paper sheets, because the tape is always wound even in the period of time during which no paper sheets are transported.
Another approach designed for intermittently winding the tape has been known (e.g., see Patent Document 1). In this approach, the winding roller is driven to start the winding operation for the tape once the paper sheets are detected to be transported to the winding roller, while the winding roller is operated to stop the winding operation for the tape during the period of time in which no paper sheets are transported to the winding roller.
In the approach for successively winding the tape, the transport pitch for the paper sheets transported to the winding roller is reflected in the storing pitch for the paper sheets stored in or around the winding roller. Therefore, when the transport pitch is constant, the storing pitch is also constant. Meanwhile, in the approach for intermittently winding the tape, the winding roller is started at fixed start timing once the paper sheets are detected to be transported thereto. Thus, the storing pitch is kept nearly constant, regardless of the transport pitch. Accordingly, in both of such approaches, when the paper sheets and tape are wound around the winding roller, the outer shape of the winding roller including such paper sheets and tape is substantially circular, except for some particular cases.
For instance, “the particular case” means herein a case in which the storing pitch is constant and in which the outer-circumferential length of the winding roller including the tape is substantially the same as n times (n is a natural number) as long as the storing pitch. In such a case, for instance, as shown in FIG. 19, the paper sheets tend to be wound around the winding roller, unevenly, in substantially the same position or positions. More specifically, FIG. 19(a) shows one case in which the outer-circumferential length of the winding roller is substantially the same as the storing pitch, and FIG. 19(b) shows another case in which the outer-circumferential length of the winding roller is substantially the same as twice as the storing pitch. Further, as used herein, “the same position or positions” means a position or positions, each located or arranged in substantially the same direction, when seen from the center of the winding roller.
Namely, in the case in which the paper sheets are wound as shown in FIG. 19, the outer shape of the winding roller including the paper sheets and tape will not be circular. Therefore, with the rotation of the winding roller, the distance between the winding roller and other parts, such as guides or the like, respectively arranged to surround the outer circumference of the winding roller, will be changed considerably, thus leading to occurrence of a negative effect, such as vibration or the like. Further, in the case as shown in FIG. 19(a), the center of gravity of the winding roller including the paper sheets and tape will not be coincident, in position, with the center of rotation of the winding roller, thus causing another negative effect, such as difficulty in controlling the rotation or the like.
By the way, in the approach for successively winding the tape, the aforementioned particular case in which the outer-circumferential length of the winding roller including the tape is substantially the same as n times (n is the natural number) as the storing pitch can be avoided, by altering the storing pitch by changing the transport pitch and/or winding speed of the paper sheets. (e.g., see Patent Document 2).
However, in the approach for intermittently winding the tape, the paper sheets respectively transported to the winding roller are wound once they are detected one by one. Therefore, the storing pitch is not changed even in the case in which the transport pitch and/or winding speed is altered. As such, the occurrence of the negative effect as described above cannot be avoided.